Updated Checked by the Tax-Services.ca editorial team How we check
If your employer did not deduct income tax, the tax is still owed. You settle it when you file, and on $65,000 of pay in Ontario that could be $9,725.50 due by April 30. Federal rules say an employer has to deduct tax from the first dollar you earn, so a missing deduction is the employer’s slip, but the bill lands on you.
Is it my problem if my employer skipped the deduction?
Mostly, yes, at least the payment. Your employer had the duty to deduct. But the tax on your pay doesn’t disappear when they don’t, and it’s calculated on your return from your total income for the year. The T4 slip your employer gives you shows the pay in box 14 and the tax they took in box 22. If box 22 is empty or low, expect to owe.
What about the employer’s own trouble? We couldn’t find an official CRA page that says how the CRA treats an employee in this case, or whether penalties for the employer pass to you. Ask the CRA directly if that worry keeps you up.
How much will I owe if nothing was withheld?
Use the tax refund calculator and enter your pay and the tax already taken. These results are for Ontario in 2026.
| Employment income | Tax withheld | Balance owing |
|---|---|---|
| $30,000 | $0 | $2,452.11 |
| $65,000 | $0 | $9,725.50 |
| $65,000 | $4,000 | $5,725.50 |
Look at the last two rows together. Same pay, but the $4,000 that was withheld in the third row comes straight off the bill, dollar for dollar. Partial withholding is common when a payroll setup is wrong, and the fix is the same: compare box 22 with what the calculator says you owe.
Those figures are income tax only. If CPP and EI weren’t taken off either, look at boxes 16 and 18 of your slip. We couldn’t confirm what happens to missing CPP and EI amounts, so ask the CRA before you assume they’re covered.
What should you do right now?
Start with the T4. If it hasn’t arrived by early April, the CRA tells you to contact your employer. Check that box 14 matches what you were paid.
Then ask your employer to fix it going forward. To have more tax deducted, you fill in a revised TD1 form and hand it in. That stops the problem growing.
Next, work out the bill and start setting money aside. On the $65,000 example, $9,725.50 is about $810 a month, so waiting until April makes it feel much bigger. Put the cash somewhere you won’t dip into it, a separate savings account being the simplest.
Do you need to pay tax instalments?
Possibly. The CRA asks for instalments when the tax you owe is more than $3,000 in the current year and also in one of the two years before ($1,800 for Quebec). If you owed nothing last year and the year before, that test doesn’t apply to you yet. The tax instalments calculator checks it. With $9,000 expected and earlier years above the limit, the payments are $2,250 on March 15, June 15, September 15 and December 15.
What happens if you pay late?
For the 2025 return, the money was due on April 30, 2026. Interest starts the next day, compounds daily, and follows a rate the CRA resets every quarter. Filing late costs extra: the penalty is a flat 5% of what you owe, then another 1% for every full month it’s overdue, capped at 12 months. Filing on time, even with a partial payment, avoids that part.
Say Priya owes $5,725.50 and files on time but can’t pay it all. She still avoids the late-filing penalty. Interest still runs on what’s unpaid, so paying what she can early keeps that cost down.
Is a missing deduction ever a sign something else is wrong?
Sometimes. If you’re paid in cash with no slip, or your employer calls you a contractor while telling you when and where to work, the question isn’t only the tax. Being an employee or being self-employed changes who deducts and what you owe. Read the CRA’s guidance on that before you file, and keep every pay record you have.
Mistakes to avoid
- Thinking no tax was taken means no tax is due.
- Leaving the pay off your return because the slip looks wrong. Report it and get the slip fixed.
- Never checking if you’re really an employee. A true contractor isn’t subject to deduction at source. The self-employed tax calculator shows a different bill, with CPP on both halves.
- Spending the pay and hoping the CRA misses it.
Our sources
Deduction duties, T4 boxes, deadlines, interest and penalties come from Canada Revenue Agency pages for the 2025 tax year, read in September 2026. Tax estimates use the 2026 federal and Ontario figures in our calculators. We’re an independent site, and no government body is behind it.
Frequently asked questions
Do I still owe tax if my employer did not deduct it?
Yes. Your tax is worked out on your return from your income for the year, so any tax not withheld is due when you file.
How can I find out what tax my employer deducted?
Look at box 22 of your T4 slip. Box 14 shows your employment income.
How do I make my employer deduct more tax?
Fill in a revised TD1 form and give it to your employer. That raises deductions from then on.
When is the balance due?
It falls on April 30 of the next year. For 2025 income that was April 30, 2026.
What if I can't pay everything on April 30?
File on time anyway. Late filing adds a penalty on top of the daily interest charged on unpaid tax.
- Self-employed taxes in Canada: income, CPP and GST
How tax works when you are self-employed in Canada: reporting income and expenses, paying both halves of CPP, instalments and when to register for GST